Light-Weighting Methodology in Rail Vehicle Design Through Introduction

KTH - Engineering Sciences Light-Weighting Methodology in Rail Vehicle Design through Introduction of Load Carrying Sandwich Panels Licentiate Thesis David Wennberg Centre for Eco2 Vehicle Design Department of Aeronautical and Vehicle Engineering TRITA AVE 2011:36 ISSN 1651-7660 ISBN 978-91-7501-002-1 Postal address: Visiting address: Royal Institute of Technology (KTH) Teknikringen 8 Telephone: +46 8 790 89 10 Aeronautical and Vehicle Engineering Stockholm E-mail: [email protected] Rail Vehicles www.kth.se/en/sci/institutioner/ave/avd/rail SE-100 44 Stockholm www.kth.se/en/sci/centra/eco2 Abstract Lightweight design in rail vehicles has been important for quite some time. Structures have been optimised to fulfill their purpose and cut unnecessary weight to reach allowable axle loads. Classically this is done by using steel, thin-walled structures, throughout the car body, or, alternatively, power-pressed aluminum profiles. The use of composites and sandwich structures has, however, been somewhat limited in the railway industry, especially when considering High-Speed trains. The anticipated weight savings, and reduced complexity of this type of structure are believed to have great potential in the future. This thesis covers the development of methods for structural stiffness design of lightweight, load carrying, sandwich panels for high-speed rail vehicles. Focus is on reducing the weight of the vehicles while simplifying the construction to reduce manufacturing costs and assembly times. Significant work is put into understanding the dynamic influence this type of structure has on the car body. Roof section Top wall section window pillars Floor section Bottom wall section z x y Figure 1: Module sandwich car body. I II Acknowledgment The work presented in this Licentiate thesis was carried out within the project Multi-functional body-panels, under the Centre for ECO2 Vehicle Design at the Royal Institute of Technology KTH in Stockholm, Sweden. The funding from Vinnova, Bombardier Transportation, SAAB automobile and A2Zound is gratefully acknowledged. Many thanks to my supervisors Professor Sebastian Stichel, div. of Rail Vehicles, and Dr. Per Wennhage, div. of Lightweight Structures, for your in- depth knowledge in your respective areas and for your support and guidance throughout the project. I would also like to thank Henrik Tengstrand, Director Specialist Engineering at Bombardier Transportation, for initiating this project together with Professor Peter Göransson,project manager of Multi-functional body panels. To all my colleagues at KTH, as well as the Specialist Engineers at Bom- bardier Transportation, thank you for the time so far, both in and out of the office. Finally, to my family and friends, for your reliance, confidence and support, thank you. Stockholm, April 2011 David Wennberg III IV Outline of Thesis This thesis contains an introductory part describing rail vehicle car body design, a general introduction to sandwich theory, the Economical and Ecological (ECO2) aspects of light-weighting in the railway industry, as well as the follo- wing appended papers: Paper A David Wennberg, Per Wennhage, and Sebastian Stichel: Orthotropic models of corrugated sheets in Finite Element analysis. Manuscript accepted for publication in ISRN Mechanical Engineering, 21 March 2011. Paper B David Wennberg, Sebastian Stichel and Per Wennhage: Corrugated sheet substi- tution by a multiple-requirement based selection process. Manuscript submitted for publication. Paper C David Wennberg, Per Wennhage, and Sebastian Stichel: Selection of Sandwich Panels for the Load Carrying Structures of High-Speed Rail Vehicles. Accepted for oral presentation at the International Conference on Composite Structures (ICCS) 16, 2011. V VI Contents 1 Introduction 1 1.1 Background . .1 1.2 Car body function and design . .1 1.2.1 Load carrying structure . .2 1.2.2 Car body dynamics . .4 2 Sandwich Design 7 2.1 Multi-functionality . .7 2.2 Sandwich structures . .9 2.2.1 Sandwich function . .9 2.2.2 Composites . 11 2.3 Sandwich structures in rail vehicles . 12 2.3.1 The Korean Tilting Train eXpress (TTX) . 12 2.3.2 C20 FICAS . 14 3 Light-weighting 15 3.1 ECO2 aspects . 15 3.2 Energy . 16 3.3 Green house gas emissions . 18 3.4 Effective rail transportation . 18 3.5 Downsizing . 19 3.6 Concerns . 19 3.7 ECO2 Overview . 21 4 Summary 23 4.1 Discussion . 23 4.2 Present work . 23 4.3 Future work . 25 Bibliography 26 5 Appended papers A-C 29 VII VIII Chapter 1 Introduction 1.1 Background Rail cars are relatively heavy in comparison to other transportation modes. As an example, the weight per seat is around three times higher for rail vehicles than for buses (X 2000, a Swedish high speed train, vs Neoplan Spaceliner [1]). In addition to this, the price of rail cars per kilogram is high. Reasons are partly short series and individual design for each customer. Conservative load assumptions in railway standards are another contributor. Today there is quite a lot of knowledge existing about properties and manufacturing possibilities of sandwich structures. Therefore a sandwich car body or a combination of a steel/aluminium car body with sandwich design is considered to be a realistic alternative to conventional steel or aluminum designs. Some applications in rail vehicles as well as busses already exist [2]. A factor that has prohibited wider use of such innovative concepts is, however, the cost aspect. 1.2 Car body function and design Definition: The car body of a rail vehicle refers to the load carrying structure, doors, windows, interior with seats etc, inner lining and so-called comfort systems for lighting, heat, ventilation and sanita- tion. The technical equipment for propulsion, braking etc is by definition not included in the car body, even though this equipment usually is attached/hinged on this (commonly under the car body). Sometimes the concept car body is limited to only the load carrying structure of the vehicle. The car body must meet a number of requirements, including: safety requirements set up for crash scenarios, derailment, fire, projectiles impacts, pressure waves in tunnels, etc. The car body must also be within the specific construction profile of the operated line. It must be strong enough as not to fail during typical maximum loads or during cyclic loading. A large amount of these requirements are, for example, covered by the norm prEN 12663-1 [3]. The design should, furthermore, be reasonably easy to manufacture and maintain, it should be possible to repair damages to the car body, while keeping 1 Life Cycle Costs (LCC) within reasonable limits. For high speed trains it is important to have a good aerodynamic design with, for example a stretched front, smooth outer surface, enclosed undercarriage, etc. The car body is also the operators face outward, placing high requirements on exterior and interior design, a modern rail vehicle should look modern. Beside these requirements, the car body must fulfill comfort requirements. For passenger vehicles the car body must provide the correct environment, e.g. a good ride comfort, the right lighting, space, temperature, fresh air and a low sound level. 1.2.1 Load carrying structure In this section two concepts for the design of the load carrying structure of car bodies are presented, one stainless steel alternative in Figures 1.1 and 1.2, and one aluminum car body in Figure 1.3. These two alternatives can be seen, on a conceptual level, as how the load carrying structure of modern high-speed rail vehicles is built. Sole bar Floor cross-beam Corrugated sheet metal in floor structure Buffer beam Enclosed undercarriage for mechanical equipment Wheelarch and vertical stiffness of car body Figure 1.1: Swedish X2 foundation in stainless steel. 2 Connection between roof beam and side bearers Roof side sill Corrugated sheet metal Side bearers Extra corrugated sheet metal to increase wall shear stiffness Gable bearer Sole bar Figure 1.2: Swedish X2 wall structure in stainless steel. Side bearer Power-pressed aluminium profiles Figure 1.3: DB ICE body structure constructed in aluminium. 3 1.2.2 Car body dynamics From a space and loading perspective, it is beneficial to have the car body as long and as wide as possible. However, as a consequence of the loading profile, which sets limits on the size of the car body cross-section, the structure can become rather long and slender with relatively low rigidity. A too flexible car body can lead to significant structural motion during operation, resulting in poor ride comfort or even structural damage of the car body. During operation the car body is continuously excited due to the dynamic interaction between track, wheels, boggie and car body. To avoid resonances, the principle of separating frequencies is employed (cf. Figure 1.4, this is also briefly mentioned in [3]). Component frames 18 Hz Inner floor with chairs 18Hz ∼ ∼ Floor between side sills 14 Hz ∼ Car body vertical bending mode 10 Hz ∼ Boggie 5-7 Hz Track Figure 1.4: The principle of separating frequencies. A common design prinicple is to keep the first natural frequency of the car body as high as possible, typically above 10 Hz. The first five natural frequencies and modes of a high-speed car body are presented in Figure 1.5 . These are the typical natural modes of a high speed car body, however, the order and frequencies may differ from this specific example. The natural frequencies of the car body give a good impression of how stiff the construction is. Especially the vertical bending mode gives a hint of how well the car body will manage the payload. (a) Vertical bending, 9.0 (b) Shearing of the cross (c) Lateral bending, 10.2 Hz. section, 9.9 Hz. Hz. (d) Breath-mode, 11.1 Hz.

Load more